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    Burst excited linear prediction
    82.
    发明专利
    Burst excited linear prediction 未知

    公开(公告)号：AU693519B2

    公开(公告)日：1998-07-02

    申请号：AU1739895

    申请日：1995-02-01

    Applicant: QUALCOMM INC

    Inventor： GARDNER WILLIAM R

    IPC: G10L19/08 ,  G10L19/00 ,  G10L19/04 ,  G10L19/12 ,  G10L5/06 ,  G10L7/08 ,  G10L9/06 ,  G10L9/14

    Abstract: A novel and improved apparatus for encoding a signal which is bursty in nature. In a code excited linear prediction algorithm, short term redundancies and long term redundancies are removed from digitally sampled speech, and the residual signal which is bursty in nature must be encoded. The residual signal is encoded using three parameters a burst shape index corresponding to a burst shape in a codebook of burst shapes, a burst gain, and a burst location. Together the three parameters specify a waveform to match the residual signal. Further disclosed is a closed loop exhaustive search method by which to find the best match to the residual waveform and a partially open loop method wherein the burst location is determined by an open loop analysis of the residual waveform, and the burst shape and gain parameters are determined in a closed loop fashion. Also disclosed are methods by which a burst vector codebook may be provided which may result in reduced computational complexity in the search algorithms including a recursive burst codebook and a codebook structured in such a way that members of the codebook are linear combinations of other members of the codebook.

    85.
    发明专利
    未知

    公开(公告)号：FI980207A0

    公开(公告)日：1998-01-29

    申请号：FI980207

    申请日：1998-01-29

    Applicant: QUALCOMM INC

    Inventor： GARDNER WILLIAM R ,  MONTA PETER ,  MANJUNATH SHARATH

    IPC: G10L19/02 ,  G10L19/00 ,  G10L19/04 ,  G10L19/06 ,  H03M7/30 ,  H03M7/36 ,  H04B14/04 ,  G10L

    Abstract: A novel and improved method and apparatus for encoding line predictive coding (LPC) data in a speech compression system using line spectral square root values is disclosed. A novel and computationally efficient procedure for determining the set of quantization sensitivities for the line spectral square root values is disclosed, which results in a computationally efficient error measure for use in vector quantization of the line spectral square root values. A novel method of weighting the quantization error is disclosed, which accumulates the quantization error in each line spectral square root value and weights that error by the sensitivity of that line spectral square root value.\!

    86.
    发明专利
    未知

    公开(公告)号：FI962968A

    公开(公告)日：1996-09-24

    申请号：FI962968

    申请日：1996-07-25

    Applicant: QUALCOMM INC

    Inventor： GARDNER WILLIAM R

    IPC: G10L19/00 ,  G10L19/08 ,  G10L19/04 ,  G10L19/12 ,  A61B

    Abstract: A novel and improved apparatus for encoding a signal which is bursty in nature. In a code excited linear prediction algorithm, short term redundancies and long term redundancies are removed from digitally sampled speech, and the residual signal which is bursty in nature must be encoded. The residual signal is encoded using three parameters a burst shape index corresponding to a burst shape in a codebook of burst shapes, a burst gain, and a burst location. Together the three parameters specify a waveform to match the residual signal. Further disclosed is a closed loop exhaustive search method by which to find the best match to the residual waveform and a partially open loop method wherein the burst location is determined by an open loop analysis of the residual waveform, and the burst shape and gain parameters are determined in a closed loop fashion. Also disclosed are methods by which a burst vector codebook may be provided which may result in reduced computational complexity in the search algorithms including a recursive burst codebook and a codebook structured in such a way that members of the codebook are linear combinations of other members of the codebook.

    METHOD AND APPARATUS FOR SELECTING AN ENCODING RATE IN A VARIABLE RATE VOCODER
    87.
    发明专利
    METHOD AND APPARATUS FOR SELECTING AN ENCODING RATE IN A VARIABLE RATE VOCODER 未知

    公开(公告)号：CA2171009A1

    公开(公告)日：1996-02-22

    申请号：CA2171009

    申请日：1995-08-01

    Applicant: QUALCOMM INC

    Inventor： DEJACO ANDREW P ,  GARDNER WILLIAM R

    IPC: G10L19/24 ,  G10L19/00 ,  G10L19/04 ,  G10L19/14 ,  G10L21/02 ,  G10L25/78 ,  H03M7/30 ,  G10L19/02

    Abstract: The present invention provides a method by which to reduce the probality of coding low energy unvoiced speech as background noise. An encoding rate is determined by dividing the input signal into subbands using digital subband filters (4) and (6) and comparing the energy in those bands to a set of thresholds in subband rate decision elements (12) and (14) and then examining those comparisons in an encoding rate selector (16). By this method, unvoiced speech can be distinguished from background noise. The present invention, also, provides a means for setting the threshold levels using the signal to noise ratio of the input signal, and the present invention provides a method for coding music through a variable rate vocoder by examining the periodicity of the input signal to distinguish the music from background noise.

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